wickchart-sessions

Market session shading for wickchart, as an opt-in plugin layer — the core stays session-free. Zero dependencies.

Translucent session bands (Asia / London / New York, or your own definitions) under the price action, optional closed-weekend shading, and labels at the top of each band. Sessions are plain config: presets for crypto & forex use the common UTC convention; equity/futures presets use IANA timezones, so 09:30 is the real 09:30 across DST changes. Bands ride zoom & pan and hover events tell you which session the crosshair is in.

npm install wickchart wickchart-sessions   // the plugin is a separate package

import 'wickchart';                          // the chart itself
import { attachSessions } from 'wickchart-sessions';

const chart = document.querySelector('wick-chart');
const sessions = attachSessions(chart, { preset: 'crypto' });

sessions.setPreset('nyse');   // 'crypto' | 'forex' | 'nyse' | 'cme' | null
sessions.setSessions([...]);  // custom defs — replaces the preset
sessions.setWeekends(true);   // shade closed Sat+Sun (default for nyse/cme)
sessions.setLabels(false);    // band labels at the top (default on)
sessions.setOpacity(0.12);    // band fill alpha (default 0.08)
sessions.detach();

// which session is the crosshair in?
chart.addEventListener('wick:sessions', (e) => status.textContent = e.detail.hover || '');

Custom defs — { name, start, end, tz?, days?, color?, alpha? }:

sessions.setSessions([
  { name: 'NY RTH', start: '09:30', end: '16:00', tz: 'America/New_York',
    days: [1, 2, 3, 4, 5], color: '#4c8dff' },        // DST-exact, weekdays
  { name: 'Overnight', start: '18:00', end: '06:00', utcOffset: 0 }, // crosses midnight
]);

• end <= start crosses midnight into the next day. end: '24:00' (or '00:00') ends at midnight.
• tz is any IANA name (DST-aware); utcOffset is fixed minutes east of UTC; neither means UTC.
• days filters on the band's start weekday in the session timezone (0 = Sunday).
• color is a hex, or up / down / accent for theme colors; uncolored sessions cycle through four default tints.
• Defs are normalized and validated — invalid entries are dropped, never thrown. getSessions() returns the active, JSON-serializable list.

Presets: crypto (Asia 00–08, London 07–16, New York 12–21 UTC), forex (+ Sydney 21–06, Tokyo 00–09 UTC), nyse (09:30–16:00 America/New_York, weekdays, weekends shaded), cme (08:30–15:00 America/Chicago, weekdays, weekends shaded).

The hover bridge listens to the chart's own crosshair events, so shading never claims a pointer gesture — pan/zoom/measure work untouched.

Peer dependency: wickchart ≥ 1.4.0 (the plugin layer API).